Overheating prevention apparatus and projection apparatus

ABSTRACT

An overheating prevention apparatus for use in a display apparatus is provided. The display apparatus comprises at least one fan running at at least one initial rotation speed. The overheating prevention apparatus comprises a first temperature sensor, a second temperature sensor and a processing module. The first temperature sensor is used for sensing an environment temperature and generating a first signal according to the environment temperature. The second temperature sensor is used for sensing an inner temperature of the display apparatus and generating a second signal according to the inner temperature. The processing module adjusts the at least one fan from the at least one initial rotation speed to at least one first running rotation speed according to the first signal and the second signal. The display apparatus using the present invention can automatically adjusts the speed of the fan so that the display apparatus works correctly.

This application claims priority to Taiwan Patent Application No. 099130504 filed on Sep. 9, 2010, which is hereby incorporated by reference in its entirety.

CROSS-REFERENCES TO RELATED APPLICATIONS

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an overheating prevention apparatus for use in a display apparatus, and more particularly, to an overheating prevention apparatus for use in a display apparatus, which can automatically adjust the rotation speed of a fan according to different environments.

2. Descriptions of the Related Art

With the development of science and technology, display apparatuses have become indispensable electronic products to people's life. Among such display apparatuses, projection apparatuses for large-scale screens are even more widely used in, for example, conference rooms, home theaters, classrooms and the like. Because of the wide application thereof, projection apparatuses are often used in various environments. Furthermore, light emitting elements of the projection apparatuses will generate massive heat energy during operation, so in order to ensure that the projection apparatuses will not be shut down due to overheating, most of the projection apparatuses are used in combination with heat sinks such as fans.

However, fans usually generate unavoidable noises during operation, and this has an influence on the service quality, particularly when the fans run at a high rotation speed. Accordingly, many ways of controlling fans have been developed to adjust the rotation speed of the fans correspondingly. Among such approaches, a common approach is to adjust the fan manually, which is inexpensive and simple in design and only requires the user to determine through sensation the temperature of the projection apparatus to manually set the rotation speed of the fan. However, if a false determination is made, it will easily cause damage to the elements of the projection apparatus.

Additionally, there is also an approach to automatically set the rotation speed of a fan by using a temperature sensor. This approach mainly relies on the temperature sensor in a projection apparatus to determine the operating temperature and, accordingly, adjust the rotation speed of the fan automatically. Although the automatic method is better than manual adjustment, the conventional way of automatically sensing the temperature usually operates in the following way: a temperature threshold is set, and if the temperature of the projection apparatus goes higher than the temperature threshold, then the rotation speed of the fan is increased; conversely, if the temperature of the projection apparatus goes lower than the temperature threshold, then the rotation speed of the fan is decreased. In this way, if the operating temperature of the projection apparatus is close to the temperature threshold, then the fan will run at a fluctuating rotation speed due to the instantaneous rise or fall in the temperature. Consequently, apart from the failure to obtain the preferred balance between the rotation speeds of the fan, the noises of the fan and the operating temperature, the service life of the fan may further be shortened.

Furthermore, when the projection apparatus is used at different heights above the sea level, the operating environment may be determined by using a pressure sensor so that the rotation speed of the fan is adjusted according to the height above sea level. However, the method in which the height is determined by using the pressure sensor is very costly, so it is not widely accepted by the public.

Accordingly, a need still exists in the art to solve the aforesaid problem so that the projection apparatus can adjust the heat dissipation device according to different environments and an optimal balance can be achieved between the heat dissipation, the noises and the price simultaneously.

SUMMARY OF THE INVENTION

To solve the aforesaid problem, an objective of the present invention is to provide an overheating prevention apparatus for use in a display apparatus. By using the overheating prevention apparatus, the display apparatus can adjust the rotation speed of a fan of the overheating prevention apparatus automatically and evenly according to different operating environments to ensure proper operation of both the overheating prevention apparatus and the display apparatus.

To accomplish the aforesaid objective, the present invention provides an overheating prevention apparatus for use in a display apparatus. The display apparatus comprises at least one fan, and the at least one fan runs at at least one initial rotation speed. The overheating prevention apparatus comprises a first temperature sensor, a second temperature sensor and a processing module. The first temperature sensor is configured to sense the temperature in the environment and generate a first signal according to the environment temperature. The second temperature sensor is configured to sense the inner temperature of the display apparatus and generate a second signal according to the inner temperature. The processing module is configured to adjust the at least one fan from the at least one initial rotation speed to at least one first running rotation speed according to the first signal and the second signal.

Another objective of the present invention is to provide a projection apparatus, which comprises at least one fan, a first temperature sensor, a second temperature sensor and a processing module. The at least one fan runs at at least one initial rotation speed. The first temperature sensor is configured to sense the temperature in the environment and generate a first signal according to the environment temperature. The second temperature sensor is configured to sense an inner temperature of the projection apparatus and generate a second signal according to the inner temperature. The processing module is configured to adjust the at least one fan from the at least one initial rotation speed to at least one first running rotation speed according to the first signal and the second signal.

According to the above descriptions, the present invention can employ the two sensors of the display apparatus to detect the environments to generate operating parameters in the various environments, and according to the operating parameters, further adjust the fan of the display apparatus automatically and evenly so that the display apparatus can operate normally in the various environments.

The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a display apparatus of the present invention;

FIG. 2A shows a first corresponding relation table of the present invention;

FIG. 2B is a coordinate graph of the first corresponding relation table of the present invention;

FIG. 3A shows a second corresponding relation table of the present invention; and

FIG. 3B is a coordinate graph of the second corresponding relation table of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following description, an overheating prevention apparatus of the present invention will be explained with reference to embodiments thereof. It shall be appreciated that the embodiments of the present invention are not intended to limit the present invention to any specific environment, applications or particular implementations described in these embodiments. Therefore, the description of these embodiments is only for the purpose of illustration rather than to limit the present invention.

FIG. 1 illustrates a schematic view of a display apparatus 1 of the present invention. It shall be particularly appreciated that in this embodiment, the display apparatus 1 is a projection apparatus; however, it is not limited thereto, and the display apparatus 1 may be any other display equipment in which overheating has to be prevented. The display apparatus 1 comprises a fan 11 and an overheating prevention apparatus 13. The overheating prevention apparatus 13 further comprises a first temperature sensor 131, a second temperature sensor 133 and a processing module 135 comprising a memory 137.

After the display apparatus 1 is turned on, the fan 11 runs at an initial rotation speed. Then, the first temperature sensor 131 detects an environment temperature T_(i) of the environment where the display apparatus 1 is located and, according to the environment temperature T_(i), generates a first signal 132, which is then transmitted to the processing module 135. The second temperature sensor 133 detects an inner temperature T_(c) of the display apparatus 1 and, according to the inner temperature T, generates a second signal 134, which is also transmitted to the processing module 135. Then, according to the first signal 132 and the second signal 134, the processing module 135 adjusts the fan 11 from the initial rotation speed to a first running rotation speed.

In detail, after being started up, the processing module 135 firstly determines the initial rotation speed of the fan 11 to facilitate heat dissipation in the start-up process; and after the display apparatus 1 has run for a default time period, the processing module 135 determines the environment temperature T_(i) according to the first signal 132 transmitted by the first temperature sensor 131 and the inner temperature T_(c) of the display apparatus 1 according to the second signal 134 transmitted by the second temperature sensor 133. Then, the processing module 135 determines the environment height at which the display apparatus 1 is currently located according to the environment temperature T_(i), the inner temperature T_(c) and a first corresponding relation table 136 stored in the memory 137.

Next, in reference to FIG. 2A, the first corresponding relation table 136 comprises a first temperature corresponding relation 1361, a second temperature corresponding relation 1362 and a third temperature corresponding relation 1363 between the environment temperature T_(i) and the inner temperature T_(c). The method in which to determine the environment height according to C_(ij) and L_(ij) will be elucidated in the following description. Firstly, it shall be particularly appreciated that, (C₁₁, I₁₁), (C₁₂, I₁₂), (C₁₃, I₁₃), (C₁₄, I₁₄) and (C₁₅, I₁₅) in the first temperature corresponding relation 1361 generally exhibit a linear relation; therefore, for ease of understanding, the first temperature corresponding relation 1361 is depicted as a line segment 21 in a coordinate graph of FIG. 2B. Similarly, the second temperature corresponding relation 1362 and the third temperature corresponding relation 1363 are also depicted as a line segment 22 and a line segment 23 respectively for the purpose of the following description.

First, the processing module 135, with a value of the environment temperature T_(i) as a reference point, determines the environment height according to the value of the inner temperature T_(c). For example, when the processing module 135 determines that the value of the environment temperature T_(i) is I₁, the processing module 135, according to a relation represented by the first temperature corresponding relation 1361 (the line segment 21), determines whether the inner temperature T_(c) exceeds the value C₁₁ corresponding to I₁ in the first temperature corresponding relation 1361 to determine the environment height. In more detail, when the value of the environment temperature T_(i) is I₁, the processing module 135 determines that the value of the inner temperature T_(c) is smaller than or equal to C₁₁, then the environment height is within a first environment height range R₁ defined by the first temperature corresponding relation 1361.

On the contrary, when the value of the environment temperature T_(i) is I₁, the processing module 135 determines that the value of the inner temperature T_(c) is greater than C₁₁, then this means that the environment height has exceeded the first environment height range R₁. In this case, according to the second temperature corresponding relation 1362, the processing module 135 further determines whether the environment height is within a second environment height range R₂ defined by the second temperature corresponding relation 1362.

In more detail, after determining that the environment height has exceeded the first environment height range R₁, the processing module 135 similarly determines the environment height according to the value of the inner temperature T_(c) with the value of the environment temperature T_(i) as the reference point. For example, after the processing module 135 determines that the value of the environment temperature T_(i) is I₁ and the value of the inner temperature T_(c) is greater than C₁₁, the processing module 135, according to a relation represented by the second temperature corresponding relation 1362 (the line segment 22), determines whether the value of the inner temperature T_(c) is smaller than or equal to C₂₁. If the answer is “yes”, this represents that the environment height is within the second environment height range R₂; otherwise, if the answer is “no”, then according to the third temperature corresponding relation 1363, the processing module 135 further determines whether the environment height is within a third environment height range R₃ defined by the third temperature corresponding relation 1363. Similarly, subsequent determining operations are identical to those of the aforesaid process flow, and thus, will not be further described herein.

After determining the environment height, the processing module 135 first adjusts the fan 11 from the initial speed to the first running rotation speed according to the environment height so that the heat dissipation mode corresponding to the environment height of the display apparatus 1 is used. Then, after determining the environment height of the display apparatus 1 and the first running rotation speed, the processing module 135 determines a new rotation speed of the fan 11 according to a second corresponding relation table 138 stored in the memory 137.

It shall be particularly appreciated that the second corresponding relation table 138 has recorded therein relations between the environment temperature T_(c) and the first running rotation speed when the display apparatus 1 is within the first environment height range R₁, the second environment height range R₂ or the third environment height range R₃ respectively. According to this, the fan 11 is adjusted from the first running rotation speed to a second running rotation speed. In brief, the processing module 135 adjusts the rotation speed of the fan 11 again according to the environment temperature T_(c) represented by the first signal 132 and the second corresponding relation table 138.

Next, in reference to FIG. 3A, the second corresponding relation table 138 comprises a first rotation speed relation 1381, a second rotation speed relation 1382 and a third rotation speed relation 1383 between the environment temperature T_(i) and the first running rotation speed when the display apparatus 1 is within the first environment height range R₁, the second environment height range R₂ and the third environment height range R₃ respectively. Likewise, for ease of understanding, the first rotation speed relation 1381 is depicted as a line segment 31 in a coordinate graph of FIG. 3B. Similarly, the second rotation speed relation 1382 and the third rotation speed relation 1383 are also depicted as a line segment 32 and a line segment 33 respectively for purposes of the following description.

In detail, when the display apparatus 1 is within the first environment height range R₁, a corresponding relation between the rotation speed of the fan 11 and the environment temperature T_(i) is as shown by the first rotation speed relation 1381 (the line segment 31). For example, if the display apparatus 1 is within the first environment height range R₁, then when the value of the environment temperature T_(i) is equal to I₆, the fan 11 is adjusted to a rotation speed of W₁₂.

Similarly, when the display apparatus 1 is within the second environment height range R₂, a corresponding relation between the rotation speed of the fan 11 and the environment temperature T_(i) is as shown by the second rotation speed relation 1382 (the line segment 32). For example, if the display apparatus 1 is within the second environment height range R₂, then when the value of the environment temperature T_(i) is equal to I₇, the fan 11 is adjusted to a rotation speed of W₂₃. In other conditions, the rotation speed of the fan 11 is adjusted in a similar way, and this will not be further described herein.

It shall be particularly emphasized that to ensure the normal operation of the display apparatus 1 more completely, the memory 137 further stores a first upper bound value C_(limit), and when the environment temperature T_(i) exceeds the first upper bound value C_(limit), the processing module 135 shuts down the display apparatus 1 according to the first signal 132. The memory 137 further stores a second upper bound value I_(limit), and when the inner temperature T_(c) exceeds the second upper bound value I_(limit), the processing module 135 shuts down the display apparatus 1 according to the second signal 134. In this way, by means of the first upper bound value C_(limit) and the second upper bound value I_(limit), the display apparatus 1 can be more completely protected from overheating.

According to the above descriptions, the display apparatus 1 first determines a height at which it is located according to the environment temperature T_(c), the inner temperature T_(i) and what was recorded in the first corresponding relation table 136, and then determines a rotation speed of the fan 11 based on the height at which the display apparatus 1 is located and according to the environment temperature T_(c) and what was recorded in the second corresponding relation table 138. In this way, an optimal balance between the temperature and the noises can be obtained at a lower cost and with a higher control accuracy, thereby accomplishing an efficacy that would be impossible in the prior art.

The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended. 

What is claimed is:
 1. An overheating prevention apparatus for use in a display apparatus, the display apparatus comprising at least one fan, the at least one fan running at at least one initial rotation speed, the overheating prevention apparatus comprising: a first temperature sensor, being configured to sense an environment temperature and generate a first signal according to the environment temperature; a second temperature sensor, being configured to sense an inner temperature of the display apparatus and generate a second signal according to the inner temperature; and a processing module, being configured to adjust the at least one fan from the at least one initial rotation speed to at least one first running rotation speed according to the first signal and the second signal.
 2. The overheating prevention apparatus as claimed in claim 1, wherein the processing module further comprises: a memory, being configured to store a first corresponding relation table of the environment temperature and the inner temperature; wherein the processing module determines an environment height according to the first signal, the second signal and the first corresponding relation table during a default time period, and adjusts the at least one fan from the at least one initial rotation speed to the at least one first running rotation speed according to the environment height.
 3. The overheating prevention apparatus as claimed in claim 2, wherein the memory is further configured to store a second corresponding relation table of the environment temperature and the at least one first running rotation speed, and the processing module is further configured to adjust the at least one fan from the at least one first running rotation speed to at least one second running rotation speed according to the first signal and the second corresponding relation table.
 4. The overheating prevention apparatus as claimed in claim 2, wherein the memory is further configured to store a first upper bound value, and the processing module is configured to shut down the display apparatus according to the first signal while the environment temperature is over the first upper bound value.
 5. The overheating prevention apparatus as claimed in claim 2, wherein the memory is further configured to store a second upper bound value, and the processing module is configured to shut down the display apparatus according to the second signal while the inner temperature is over the second upper bound value.
 6. A projection apparatus, comprising: at least one fan, wherein the at least one fan runs at at least one initial rotation speed; a first temperature sensor, being configured to sense an environment temperature and generate a first signal according to the environment temperature; a second temperature sensor, being configured to sense an inner temperature of the projection apparatus and generate a second signal according to the inner temperature; and a processing module, being configured to adjust the at least one fan from the at least one initial rotation speed to at least one first running rotation speed according to the first signal and the second signal.
 7. The projection apparatus as claimed in claim 6, wherein the processing module further comprises: a memory, being configured to record a first corresponding relation table of the environment temperature and the inner temperature; wherein the processing module determines an environment height according to the first signal, the second signal and the first corresponding relation table during a default time period, and adjusts the at least one fan from the at least one initial rotation speed to the at least one first running rotation speed according to the environment height.
 8. The projection apparatus as claimed in claim 7, wherein the memory is further configured to store a second corresponding relation table of the environment temperature and the at least one first running rotation speed, and the processing module is further configured to adjust the at least one fan from the at least one first running rotation speed to at least one second running rotation speed according to the first signal and the second corresponding relation table.
 9. The projection apparatus as claimed in claim 7, further comprising a power circuit, wherein the memory is further configured to store a first upper bound value, and the processing module is configured to shut down the projection apparatus by controlling the power circuit according to the first signal while the environment temperature is over the first upper bound value.
 10. The projection apparatus as claimed in claim 7, further comprising a power circuit, wherein the memory is further configured to store a second upper bound value, and the processing module is configured to shut down the projection apparatus by controlling the power circuit according to the second signal while the inner temperature is over the second upper bound limit. 